1,721,052 research outputs found
Crystallization Conditions and Subsolidus Modifications of Feldspars in Plutonic Complexes.
No full textAspetti genetici e strutturali dei megacristalli di feldspato potassico dei granitoidi di Satriano (Serre orientali - Calabria)
No full textLate-Hercynian plutonism in the Eastern Serre (Southern Calabria): Petrological inferences
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Il Plutonismo tardo-ercinico nelle Serre orientali (Calabria meridionale): Aspetti Petrologici.
No full textMetamorphic xenoliths and microgranular enclaves in the Serre granodiorite (Southern Calabria - Italy): Their connection with granitoid genesis
No full textEVALUATION OF NUMIDIAN QUARTZ SANDSTONES FROM SOUTHERN ITALY FOR INDUSTRIAL APPLICATIONS
No full textNumidian quartz-rich sandstones collected from four different reconstructed sections along the Apennine chain of Southern Italy, have been studied for their textural, petrographic and geochemical characteristics to verify their potential industrial use. Sampling was carried out along a NW-SE transect: Monteverde and Aquilonia sections at NW (Campania Region) and Valsinni and Rotondella ones at SE (Lucania Region). The sandstones from NW successions are subarkoses with subordinate sublitharenites. High compositional maturity is shown by these sandstones containing high SiO2 values (93wt% in average) and lowest amounts of CaO (0.08 wt%), MgO (0.1wt%), Fe2O3 (0.9 wt%) due to the absence of carbonate components (cement and lithics) and scarce presence of clay-ferruginous cement. The sandstones from SE successions show lower contents of SiO2 (87 wt% in average) and relatively higher contents of CaO (up to 7.4 wt%), MgO (up to 1.9 wt%) and Fe2O3 (up to 4.6 wt%) as compared to the previous ones, connected to the presence of calcite and clay-ferruginous cements; these can be classified as Fe-sands with subordinate sublitharenites. The sandstones from NW area show a better potential vocation to be used in the glass industry. However, the coloring elements contents are too high for clear or optical glass production. They are it is suitable as raw material for colored glass, insulating fibres, foundry molds or air Crete. With the aim of assessing the possible improvement of chemical characters, four granulometric fractions (A< 63 μm, B 63-125 μm, C 125-250 μm and D >250μm) were analyzed considering four samples from NW successions. Based on chemical composition, C and D fractions from Aquilonia area, are the most suitable for a coloured glass, while fractions A (<63 μm) and B (63-125 μm) mixed in proportions of 40 % (A) and 60 % (B), appropriately cleaned of clays, heavy minerals and iron hydroxides, could be used as raw material for the paint industry. The obtained results suggest a complete exploitation of this type of sandstones in the manufacturing industry, reducing waste materials and enhancing the economic value of these resources from southern regions of Italy
Mineral and chemical provenance indicators in some early Miocene sandstones of the Southern Apennines (Italy)
No full textBlue-amphibole bearing arenites from Southern Apennines (Italy): inferences on their provenance
No full textGeochemistry and potential industrial use of Numidian sandstones from Southern Apennines (Italy)
Full text linkABSTRACT
Forty-nine samples of quartz-rich sandstones collected in the Numidian Flysch of Southern Apennines (Italy) have been studied to highlight their geochemical characteristics and to check their potential industrial use. Sampling was performed from five different depositional sequences along a NW-SE traverse: Monteverde (MV, n=8), Aquilonia (AQ, n=8), Pietragalla (PQZ, n=16), Rotondella (RO, n=6) and Valsinni (VAL, n=8). The sandstones derived from NW successions (MV, AQ and PQZ) show a major compositional maturity with higher contents in SiO2 (93% wt in average), K2O (around 1% wt) and Rb (25 ppm), connected with the presence of K-feldspar and micas; they show lower contents of CaO (0,1% wt), Sr, MgO (0,10% wt) and Fe2O3 (0,9% wt) owing to the absence of carbonatic and clay-ferruginous cements. The sandstones from SE sequences (RO and VAL) show lower contents of SiO2 (88% wt in average), K2O (0.3% wt in average) and Rb (9 ppm) and higher contents of CaO, MgO and Fe2O3. According to Herron (1988) classification, the sandstones from NW are subarkoses and sublitharenites, whereas those from SE fall mainly in the Fe-sand field. The sandstones from NW area show a potential vocation to use in the glass industry; to test this capability, four samples from these sequences were analysed considering different granulometric fractions. Chemical analyses were performed on four granulometric fractions (A250μm). The C and D fractions represent the most suitable for a vitrifiable mix because they are the most rich-SiO2 (around 96% wt) and the poorest in contaminant elements (Fe2O3=1,25-0,30%, Al2O3=3,63-1,97%, MgO=0,14-0%, CaO=0,1-0,02%). However, C and D fractions fall outside the granulometric range required by the glass industry, this problem can be easily solved subjecting them to further grinding. A and B fractions result less suitable for glass industry owing to their chemical characteristics (SiO2=93,7–77,2%, Fe2O3=3,35-0,44%, Al2O3=10,7-3,5%, MgO=0,41-0,03%, CaO=0,4-0,03%), on the other hand, these fractions are the most abundant (A+B≈ 80% in weight against C+D ≈20% in weight). We suggest that after additional treatments (ultrasound washing, magnetic and electrostatic separation, and chemical dissolution) even these fractions could be used in glass industry. Overall the Numidian sandstones from Southern Italy seem suitable for glass industrial uses
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